PatternReplaceCharFilter crashes JVM with OutOfMemoryError [LUCENE-6079]

PatternReplaceCharFilter fills memory with input data until an OutOfMemoryError is thrown.

java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Arrays.java:3332)
at java.lang.AbstractStringBuilder.expandCapacity(AbstractStringBuilder.java:137)
at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:121)
at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:569)
at java.lang.StringBuilder.append(StringBuilder.java:190)
at org.apache.lucene.analysis.pattern.PatternReplaceCharFilter.fill(PatternReplaceCharFilter.java:84)
at org.apache.lucene.analysis.pattern.PatternReplaceCharFilter.read(PatternReplaceCharFilter.java:74)
...

PatternReplaceCharFilter should read data chunk-wise and pass the transformed output chunk-wise to the caller.

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Migrated from [LUCENE-6079](https://issues.apache.org/jira/browse/LUCENE-6079) by Alexander Veit
Environment:
```
Microsoft Windows, x86_64, 32 GB main memory
```

Inspect PatternReplaceCharFilter.java, especially read and fill at the stack-trace lines, to understand how input accumulates. Reproduce the failure with large input and verify that transformed output is delivered chunk-wise without unbounded buffering or an OutOfMemoryError.

Written by the indexing model from the issue text.